Digital Hand Model Reconstructing the Morphology and Posture

本研究的目的是(1)获得覆盖日本人手形态变化的具有代表性的3D手形；(2)重建数字手模型的抓握姿势。研究结果如下：1.提出了一种从3种不同姿势下拍摄的MRI图像中获取手指关节旋转轴的方法。提取骨骼表面，根据相邻两块骨骼的相对位置计算旋转轴。发现掌指关节和近、远指间关节的旋转轴并不平行，且旋转轴相对于近端骨骼的方向随屈曲角度的不同而变化。2.提出了一种由光学运动捕捉数据建立单个连杆结构模型的方法。利用该连杆模型，捕获了抓取5个不同直径气缸的姿势。捕捉到的数据被用来产生在捕捉到的圆柱之间抓住任意直径的圆柱体所需的姿势。在重建姿势时，考虑了抓取圆柱体的策略。3.根据男性受试者在3种不同姿势下拍摄的CT图像，建立了一个通用的手模型。通用模型包括皮肤和骨骼的表面多边形模型、连杆结构和功能旋转中心。4.根据100名男性和女性受试者的手部尺寸，计算了一个边界家庭9个成员的手部尺寸。通过变形通用模型来创建9个虚拟手的形状模型，使得通用模型的尺寸与每个虚拟形式的尺寸相同。5.从先前研究中获得的X光片测量骨骼长度，并分析连杆长度的异速生长

The purposes of the present study were (1)to obtain representative 3D hand forms covering the variations in the Japanese hand morphology, and (2)to reconstruct grasping postures for a digital hand model. The following results were obtained.1.A method was proposed to obtain the rotation axis of finger joints from MRI images taken in 3 different postures. Bone surfaces were extracted, and the rotation axis was calculated from the relative position of 2 adjacent bones. It was found that rotation axes of metacarpo-pharangeal and proximal and distal inter-phalangeal joints were not parallel, and that the direction of the rotation axis relative to the proximal bone changes according to the flexion angle.2.A method was proposed to obtain an individual link structure modeled from optical motion capture data. Using the link model, postures to grasp 5 cylinders of different diameter were captured. The captured data was utilized to generate postures required to grasp cylinders of arbitrary diameter between the captured ones. When a posture is reconstructed, the strategy for grasping a cylinder was taken into consideration.3.A generic hand model was created from CT images of a male subject taken in 3 different postures. The generic model consists of the surface polygon models of the skin and bones, link structure, and functional rotation centers.4.From the hand dimensions measured on 100 male and female subjects, hand dimensions of 9 members of a boundary family were calculated. Shape models of the 9 virtual hands were created by deforming the generic model so that the dimensions of the generic model become identical to those of each of virtual forms.5.Bone lengths were measured from X-ray films obtained in a previous study, and analyzed for the allometry of link lengths